This invention relates to photographic film processing and, more particularly, to a method and apparatus for rapid access processing of both sides of discrete components of photographic films.
The term "rapid access", as used herein and in the appended claims, is intended to delineate a type of photographic film or film processing which is capable of providing an image on a substrate when has been exposed directly to light defining the image or to which an image is transferred from another image or image facsimile bearing medium, by application of a processing fluid layer over the area of the image to be provided. The most common form of rapid access film processing is the diffusion transfer process used in the field of instant photography, and in which a processing fluid is spread over the surface of a sheet or web carried exposed photosensitive emulsion so that the unexposed grains of silver halide in the emulsion layer are transferred to a positive image receiving layer or layer interface.
Sheet-form films currently in use in instant photography are in the nature of preassembled film units in which each unit contains a pod of processing fluid to be distributed completely over the area of photochemicals sandwiched between two sheets of the assembly as the exposed unit is passed to the pressure nip between a pressure roller pair or equivalent. Because of the costs incident to assembling such units during manufacture, interest has arisen recently in providing rapid access films in discrete component form for appropriate exposure and processing procedures. In this latter connection, rapid access film sheets have been developed for use in recording x-ray images, for example, where a transparent substrate having photochemical layers on opposite sides is exposed to provide complementing images on opposite sides of the substrate upon exposure and processing.
The problems incident to processing such a film sheet by the application of processing fluid to opposite sides thereof are manifold. For example, some provision must be made for handling the sheet during the application of processing fluid on opposite sides as well as retaining the sheet over an adequate imbibition time for the processing fluid to interact with the photochemical layers on opposite sides of the sheet. An additional problem is presented where the nature of the exposed double-sided film sheet, coated on opposite sides with the processing fluid, requires a relatively air-tight environment for the imbibition time. In this latter respect, some types of rapid access films become sensitive to oxidation after the processing fluid is applied. Further problems involve the handling of the processing fluid where there are no preassembled film units, and the trouble and expense of providing pods or other containers for the processing fluid.